GX240 GX270 GX340 GX390 UT2/RT2 Technical Manual ©2010 American Honda Motor Co., Inc. PTR54179 All Rights Reserved GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual Preface This manual covers engine selection, engine installation design and engine installation testing, so the combination of a Honda engine and your equipment will make the best possible product. Please feel free to contact your Honda Engine Distributor at any time for additional technical information or to discuss your engine application needs. All information contained in this manual is based on the latest product information available at the time of printing. We reserve the right to make changes at anytime without notice. No part of this publication may be reproduced, or transmitted, in any form or by any means, electronic, mechanical photocopying, recording or otherwise, without the prior written permission of the publisher. This includes text, figures and tables. Contents Design Features .......................................................... 2 Starting Performance ...........................................16 Emission Regulations ................................................. 2 Installation Considerations ........................................17 Recommended Power Range ..................................... 3 Maintenance Points Accessibility ........................17 Maximum Operation ............................................... 3 Dimensional Drawings ...............................................19 Continuous Operation ............................................ 3 GX240-270 ...........................................................19 Power Curve .......................................................... 3 GX340-390 ...........................................................23 Output Confirmation Methods ................................ 5 PTO Dimensional Drawings ......................................27 Cooling ....................................................................... 5 H Type (with reduction) ........................................27 Minimum Cooling Air Flow Requirement ................ 5 L Type (with reduction) .........................................27 Ambient Temperature Limits .................................. 5 P Type ..................................................................28 Testing ................................................................... 5 Q Type ..................................................................28 Engine Enclosures ................................................. 6 S Type ..................................................................29 Fuel System ................................................................ 7 V Type ..................................................................29 Fuel Tank Position ................................................. 7 W Type .................................................................30 Fuel Line ................................................................ 7 Dimensions and Weights ...........................................31 Fuel Valve Installation ............................................ 7 GX240 ..................................................................31 Fuel Pump ............................................................. 7 GX270 ..................................................................33 Fuel Tank Filter Installation .................................... 7 GX340 ..................................................................34 Controls ....................................................................... 7 GX390 ..................................................................35 Engine Switch ........................................................ 7 Specifications ............................................................36 Carburetor Controls ............................................... 8 GX240 ..................................................................36 Exhaust System .......................................................... 9 GX270 ..................................................................36 Recommended Muffler ........................................... 9 GX340 ..................................................................37 Fabricated Exhaust Systems ................................. 9 GX390 ..................................................................38 Engine Mounting ....................................................... 10 Serviceability .............................................................39 Inclination ............................................................. 10 Maintenance Schedule .........................................39 Resonance Check ............................................... 10 Engine Oil Level Check ........................................40 Engine Oil Change ...............................................41 Electrical System ...................................................... 11 Air Cleaner Check/Cleaning and Replacement ....41 Battery ................................................................ 11 Sediment Cup Cleaning .......................................44 Fuse ..................................................................... 11 Spark Plug Check/Adjustment ..............................45 Engine Switch ...................................................... 11 Spark Plug Replacement ......................................46 Charging Coil Selection ....................................... 12 Spark Arrester Cleaning (if equipped) ..................46 Lamp Coil Kit (optional) ........................................ 12 Idle Speed Check/Adjustment ..............................47 Oil Alert® System (optional) ................................ 12 Valve Clearance Check/Adjustment .....................48 Wiring Precautions ............................................... 12 Combustion Chamber Cleaning ...........................49 Wiring Diagrams ....................................................... 13 Fuel Tank and Filter Cleaning ..............................50 No Charge Coil Models ........................................ 13 Fuel Tube Check ..................................................50 Electric Start Models ............................................ 13 Evaporative emissions ...............................................51 Power Transmission ................................................. 15 Types with OEM provided fuel tanks ....................51 V-Belt Connections .............................................. 15 © 2010 American Honda Motor Co., Inc — All Rights Reserved 1 GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual INTRODUCTION Honda engines are designed for minimal maintenance. When maintenance is required, the task is kept simple by providing convenient maintenance access and procedures. Honda engines use proven engine technology and design innovations to make them highly reliable engines. DESIGN FEATURES High Performance OHV design reduces thermal distortion of the cylinder. This helps maintain the optimum seal between the piston rings and cylinder, which minimizes oil and fuel consumption. Power is also maintained in extreme operating conditions. Smooth and Quiet Operation OHV design provides a reduced reciprocating mass and balanced weight distribution. The 25° inclined cylinder produces a low center of gravity for the moving parts, which further reduces vibration for quiet operation. These features, and the compact design result in extremely smooth operation. Use of proven design technologies reduces noise from internal engine components. The hardness of reciprocating parts, the helical cut gears on the crankshaft and camshaft and the use of select materials makes these engines exceptionally quiet. The large muffler is designed to further reduce noise. Durability/Reliability Honda engines are built with quality that provides proven durability and reliability. Proven features such as OHV design and cast iron cylinder sleeve provide long life in all types of operating conditions. To further enhance the reliability of these engines, a 2-stage air cleaner system, digital electronic ignition system, mechanical centrifugal governor and proven side-draft carburetor are standard features. EMISSION REGULATIONS The Honda GX390 engines meet U.S. Environmental Protection Agency and the California Air Resources Board regulations. Honda engine distributors and equipment manufacturers that use Honda engines are required by regulation to follow this OEM technical manual. Correct engine matching ensures that the engine will be durable (and emission durable) in use. 2 © 2010 American Honda Motor Co., Inc — All Rights Reserved GX240 • GX270 • GX340 • GX390 (UT2/RT2) Technical Manual RECOMMENDED POWER RANGE Maximum Operation Operate the engine at not more than 90% of the maximum horsepower available at a given rpm. Recommended maximum operating hp = 0.9 x maximum hp Continuous Operation For continuous operation (more than 30 minutes), operate the engine at not more than 80% of the maximum horsepower available at a given rpm. Continuous recommended operating hp = 0.8 x maximum hp Power Curve GX240 GX270 (N·m) (lbf·ft) (kgf·m) (N·m) (lbf·ft) (kgf·m) 15 15 20 20 2.0 2.0 14 14 1.9 1.9 18 18 NET TORQUE 13 1.8 NET TORQUE 13 1.8 1.7 1.7 16 12 16 12 TORQUE 1.6 TORQUE 1.6 11 1.5 11 1.5 14 14 (KW) (KW) 7 (HP) (PS) 7 (HP) (PS) 9 9 9 9 6 6 8 8 8 8 NET POWER NET POWER 7 7 7 7 5 5 OUTPUT 6 6 OUTPUT 6 6 4 4 5 5 5 5 3 4 4 3 4 4 RECOMMENDED OPERATING SPEED RANGE RECOMMENDED OPERATING SPEED RANGE 2 2 20003000